An opportunity to turn things around.
Dark Souls 3: Irina of Carim, Eygon of Carim
Irina and Eygon of Carim come as a pair, although only Irina will move into Firelink Shrine permanently. Recruit this useful, upgradable miracle vendor by rescuing her from her cell in Undead Settlement. Simply speak to Eygon outside the cell once Irina is free to secure his friendship - or at least an alliance.
You can increase Irina's inventory by giving her the Braille Divine Tome of Carim and Lothric Holy Divine Tomb. If you buy all these "good" miracles from Irina, it will push her down the path to becoming a Firekeeper towards the end of the game. You'll find her in the tower near Firekeeper Shrine; she'll leave behind any dark tomes you gave her, so you can hand them over to Karla. Meanwhile, in endgame, Eygon will die in her old cell back in Undead Settlement; you can loot the Morne's Hammer from his body.
You can also give Irina the Londor Braille Divine Tome (sold by Yuria; see her entry above) Deep Braille Divine Tome. If you buy any of the "evil" miracles from these dark tomes, Irina will not become a firekeeper. What happens next depends on how far through the game you are:
- If you are in endgame and Eygon is dead, Irina will stay in her usual place at Firelink Shrine, and you'll need to completely clear her inventory to trigger her final state.
- If Eygon is still alive, Irina will move to the Iudex Gundyr bonfire, where Eygon will be waiting, and hostile.
In either case, Irina will stop offering vendor services. Put on Eygon's gloves (the Morne gloves, available to purchase from Shrine Handmaid after Eygon's death) and touch her when prompted to trigger some extra dialogue. What you do next is up to you.
While Irina and Eygon both live and thrive, Eygon is available as a summon on Road of Sacrifices and at the Dragonslayer Armour battle. He will visit you in Firelink Shrine after defeating the Abyss Watchers. If Irina dies or is touched by the darkness, Eygon will become hostile and be unavailable for summoning.